Apparatus and method for providing a uniform flow of gas

ABSTRACT

Outer distribution rings and gas distribution apparatus with outer distribution rings to deliver a gas flow to a process region of a process chamber are described. The outer distribution rings include at least one plenum in fluid communication with a plurality of openings forming a plurality of trenches to allow gas to flow from the plenum through the openings and down an inner peripheral face of the outer distribution ring.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/317,433, filed Apr. 1, 2016, the entire disclosure of which is herebyincorporated by reference herein.

FIELD

Embodiments of the disclosure generally relate to an apparatus and amethod for flowing a gas into a processing chamber. More specifically,embodiments of the disclosure are directed to linear flow apparatus fordirecting a flow of gas to a processing chamber such as an atomic layerdeposition chamber or chemical vapor deposition chamber.

BACKGROUND

In the field of semiconductor processing, flat-panel display processingor other electronic device processing, vapor deposition processes haveplayed an important role in depositing materials on substrates. As thegeometries of electronic devices continue to shrink and the density ofdevices continues to increase, the size and aspect ratio of the featuresare becoming more aggressive, e.g., feature sizes of 0.07 μm and aspectratios of 10 or greater. Accordingly, conformal deposition of materialsto form these devices is becoming increasingly important.

During an atomic layer deposition (ALD) process, reactant gases areintroduced into a process chamber containing a substrate. Generally, aregion of a substrate is contacted with a first reactant which isadsorbed onto the substrate surface. The substrate is then contactedwith a second reactant which reacts with the first reactant to form adeposited material. A purge gas may be introduced between the deliveriesof each reactant gas to ensure that the only reactions that occur are onthe substrate surface.

Some processes use multiple gases for various reasons. For example, aCVD process may mix two reactive gases in the process region of aprocess chamber while adding a third gas as a diluent or catalyticagent. Additionally, some processes may incorporate additional gasespost-processing to treat the deposited film or clean the processchamber. Therefore, there is an ongoing need in the art for improved gasdistribution apparatuses that can provide a uniform supply of separategases to the processing chamber.

SUMMARY

One or more embodiments of the disclosure are directed to edge ringscomprising a round body having a top, bottom, inner diameter with aninner diameter face and an outer diameter with an outer diameter face. Aplenum is formed in the top of the round body. The plenum has an outerperipheral face and an inner peripheral face defining a width. Aplurality of openings is in the inner peripheral face of the plenum. Theplurality of openings forms a plurality of trenches connecting theplenum with the inner diameter face. The plurality of trenches aresubstantially equally spaced about the inner peripheral face.

Additional embodiments of the disclosure are directed to gasdistribution apparatus comprising a gas distribution plate and an edgering. The gas distribution plate has an outer peripheral edge, a frontside and a back side with at least one delivery channel recessed in theback side of a gas distribution plate. The delivery channel has an inletend, an outlet end and a length. The delivery channel includes aplurality of apertures spaced along the length extending through the gasdistribution plate to the front side of the gas distribution plate. Theedge ring is around the outer peripheral edge of the gas distributionplate. The edge ring comprises a round body having a top, bottom, innerdiameter with an inner diameter face and an outer diameter with an outerdiameter face. The edge ring is positioned so that there is a gapbetween the outer peripheral edge of the gas distribution plate and theinner diameter face of the edge ring. A plenum is formed in the top ofthe round body. The plenum has an outer peripheral face and an innerperipheral face defining a width. At least one gas inlet is in fluidcommunication with the plenum. A plurality of openings are in the innerperipheral face of the plenum forming a plurality of trenches connectingthe plenum with the gap between the inner diameter face and the outerperipheral edge of the gas distribution plate. The plurality of trenchesare substantially equally spaced about the inner peripheral face.

Further embodiments of the disclosure are directed to processingchambers comprising a substrate support, a gas distribution apparatusand an edge ring. The substrate support has a top surface with a processregion above the top surface. The gas distribution apparatus comprises agas distribution plate having an outer peripheral edge, a front sidedefining a top of the process region and a back side with at least onedelivery channel recessed in the back side of a gas distribution plate.The delivery channel has an inlet end, an outlet end and a length. Thedelivery channel includes a plurality of apertures spaced along thelength extending through the gas distribution plate to the front side ofthe gas distribution plate. The edge ring is around the outer peripheraledge of the gas distribution plate. The edge ring comprises a round bodyhaving a top, bottom, inner diameter with an inner diameter face and anouter diameter with an outer diameter face. The edge ring is positionedso that there is a gap between the outer peripheral edge of the gasdistribution plate and the inner diameter face of the edge ring. Aplenum is formed in the top of the round body. The plenum has an outerperipheral face and an inner peripheral face defining a width. At leastone gas inlet is in fluid communication with the plenum. A plurality ofopenings in the inner peripheral face of the plenum form a plurality oftrenches connecting the plenum with the gap between the inner diameterface and the outer peripheral edge of the gas distribution plate. Theplurality of trenches are substantially equally spaced about the innerperipheral face. The gap between the inner diameter face of the edgering and the outer peripheral edge of the gas distribution plate isshaped to direct a gas to flow down the inner diameter face from theplurality of trenches out a front of the gas distribution apparatus in adirection substantially concentric with an axis of the body into anouter edge region of the process region. A supplemental gas inlet is influid communication with a supplemental gas line passing through the gasdistribution apparatus to flow a supplemental gas into the processregion. A confinement ring defines an outer edge of the process regionand comprises a plurality of openings to allow a flow of gas to passfrom the process region to exhaust.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the disclosureare attained and can be understood in detail, a more particulardescription of the disclosure, briefly summarized above, may be had byreference to the embodiments thereof which are illustrated in theappended drawings. It is to be noted, however, that the appendeddrawings illustrate only typical embodiments of this disclosure and aretherefore not to be considered limiting of its scope, for the disclosuremay admit to other equally effective embodiments.

FIG. 1 shows a view of a gas distribution apparatus in accordance withone or more embodiments of the disclosure;

FIG. 2 shows a view of a gas distribution apparatus in accordance withone or more embodiments of the disclosure;

FIG. 3 shows a view of a processing chamber including one or more gasdistribution apparatus in accordance with one or more embodiments of thedisclosure;

FIG. 4 shows a top view of a gas distribution apparatus in accordancewith one or more embodiments of the disclosure;

FIG. 5 shows a cross-section of a perspective view of a gas distributionapparatus in accordance with one or more embodiments of the disclosure

FIG. 6 shows a perspective view of a gas distribution apparatus inaccordance with one or more embodiments of the disclosure;

FIG. 7 shows a bottom view of a gas distribution apparatus in accordancewith one or more embodiments of the disclosure;

FIG. 8A shows a partial cross-sectional view of a gas distributionapparatus in accordance with one or more embodiments of the disclosure;

FIGS. 8B through 8G show partial cross-sectional views of a gas deliverychannel and apertures in accordance with one or more embodiments of thedisclosure;

FIGS. 8H and 8I show examples of the spacing between apertures in a gasdelivery channel in accordance with one or more embodiment of thedisclosure;

FIG. 8J shows an example of a gas delivery channel with varying aperturediameters in accordance with one or more embodiment of the disclosure;

FIG. 9 shows a top view of a gas distribution apparatus in accordancewith one or more embodiments of the disclosure;

FIG. 10A shows a partial cross-sectional view of a gas distributionapparatus in accordance with one or more embodiments of the disclosure;

FIGS. 10B and 10C show partial cross-sectional views of gas deliverychannels and apertures in accordance with one or more embodiments of thedisclosure;

FIG. 10D shows a front view of a gas distribution apparatus inaccordance with one or more embodiment of the disclosure;

FIG. 11 shows a view of an exploded partial cross-sectional view of agas distribution apparatus in accordance with one or more embodiments ofthe disclosure

FIG. 12 shows a cross-section of a perspective view of a gasdistribution apparatus in accordance with one or more embodiments of thedisclosure

FIG. 13 shows a perspective view of a gas distribution apparatus inaccordance with one or more embodiments of the disclosure;

FIG. 14 shows a bottom view of a gas distribution apparatus inaccordance with one or more embodiments of the disclosure;

FIG. 15 shows a perspective view of a gas distribution apparatus inaccordance with one or more embodiments of the disclosure;

FIG. 16A shows a partial cross-sectional view of a gas distributionapparatus in accordance with one or more embodiments of the disclosure;

FIG. 16B shows a partial cross-sectional view of a gas distributionapparatus in accordance with one or more embodiments of the disclosure;

FIG. 17 shows a gas distribution apparatus in accordance with one ormore embodiments of the disclosure;

FIG. 18 shows a cross-reference of a processing chamber in accordancewith one or more embodiments of the disclosure;

FIG. 19 shows a partial view of a processing chamber in accordance withone or more embodiments of the disclosure;

FIG. 20 shows a segment of a perspective view of an edge ring inaccordance with one or more embodiments of the disclosure;

FIG. 21 shows a partial perspective view of an edge ring in accordancewith one or more embodiments of the disclosure;

FIG. 22 shows a cross-sectional view of an edge ring in accordance withone or more embodiments of the disclosure;

FIG. 23 shows a cross-sectional view of an edge ring in accordance withone or more embodiments of the disclosure;

FIG. 24 shows a cross-sectional view of an edge ring in accordance withone or more embodiments of the disclosure;

FIG. 25 shows a segment of a perspective view of an edge ring inaccordance with one or more embodiment of the disclosure;

FIG. 26 shows a perspective view of a gas distribution apparatus inaccordance with one or more embodiments of the disclosure; and

FIG. 27 shows a cross-sectional view of an edge ring in accordance withone or more embodiments of the disclosure.

DETAILED DESCRIPTION

Embodiments of the disclosure are directed to gas distribution apparatusfor use in chemical vapor deposition type processes. One or moreembodiments of the disclosure are directed to atomic layer depositionprocesses and apparatus (also called cyclical deposition) incorporatingthe gas distribution apparatus described. The gas distribution apparatusdescribed may be referred to as a showerhead or gas distribution plate,but it will be recognized by those skilled in the art that the apparatusdoes not need to be shaped like a showerhead or plate. The terms“showerhead” and “plate” should not be taken as limiting the scope ofthe disclosure.

A first embodiment of the disclosure is directed to an apparatus with asingle spiral gas delivery channel. All gases flow sequentially throughthe same channel. An inlet is on the outer radial edge of the spiral,also referred to as the outer periphery, and may be attached to a gassource. A vacuum attachment is connected to the internal end of thespiral. The inlet and outlet can be reversed, either the gas source canbe connected to the inside of the spiral with the outlet valve at theoutside end of the spiral. The first embodiment can be used with asequence as shown in Table 1.

TABLE 1 Step Gas Source Outlet Valve 1  Precursor A Closed 2a PurgeClosed 2b Purge Open 2c Purge Closed 3  Precursor B Closed

A second embodiment has two spiral channels intertwined. Each channelhas a gas inlet on the outer radial end of the spiral and an outletvalve on the inner radial end of each spiral. The inlet and outlet canbe reversed or mixed. The different channels can be used for differentprecursors.

In a third set of embodiments, the channel is a linear gas line. Thelinear gas line can take any suitable shape, not just linear. There canbe multiple linear gas lines for different precursors. Some embodimentshave multiple parallel paths for all gases in sequence, whereconductance of the gas channels are substantially the same.

In one or more embodiments, in an individual channel, conductance of thegas through the channel and through the apertures is controlled bymodulating or changing the vacuum pressure at the outlet end. Changingthe vacuum pressure in turn creates a unique flow dynamic that cannot beachieved in conventional gas distribution apparatus. In someembodiments, a more uniform gas flow is provided along the length ofeach channel and through the apertures spaced along the length of thechannel. A uniform gas flow according to one or more embodiments meansthat there is substantially no dead space that inhibits flow or pumpingof gasses through the channel. The provision of a vacuum with or withouta valve on one end of the channel with a valve at the other end of thechannel permits rapid switching between different types of gases, suchas precursor or reactant gases.

In some embodiments, the vacuum at the end of the gas delivery channelenables the rapid purging of gases from within the channel. A purge gassource can be connected to the inlet of the gas delivery channel andwork cooperatively with the vacuum at the outlet of the channel to evenmore rapidly remove the reactive gases from the channel. Additionally,vacuum ports can be spaced along the length of the gas delivery channel,not just at the end of the channel.

Embodiments of the disclosure may be capable of increasing theconductance of gas through the holes spaced along the gas deliverychannel. Without being bound by any particular theory of operation, itis believed that controlling the vacuum pressure at the outlet end, orin the middle, of the channel changes the flow dynamics relative to aconventional showerhead or gas distribution plate.

Referring to FIGS. 1 and 2, one or more embodiments are directed to gasdistribution apparatus 100 to deliver a gas to a process chamber (notshown). The gas distribution apparatus 100 comprises a delivery channel102 with an inlet end 104 and an outlet end 106. The delivery channel102 has a plurality of apertures 108 spaced along the length of thedelivery channel 102. An inlet 110 is connected to and in fluidcommunication with the inlet end 104 of the delivery channel 102. Anoutlet 112 is connected to and in fluid communication with the outletend 106 of the delivery channel 102. The inlet 110 is adapted to beconnected to a gas source and may include an inlet valve 114 capable ofcontrolling the flow of gas into (or out of) the delivery channel 102 orcompletely cut off the flow of gas. The outlet 112 is adapted to beconnected to a vacuum source and may include an outlet valve 116 capableof controlling the flow of gas into (or out of) the delivery channel 102or completely cut off the flow of gas. The outlet 112 is connectable toa vacuum source (not shown) so that vacuum pressure through the outlet112 is controllable by the outlet valve 116 to provide a reducedpressure at the outlet 112.

A controller 150 regulates the flow of the gas through the deliverychannel 102 and into the process chamber. The controller 150 does thisby opening or closing (or any point in between fully open and fullyclosed) the outlet valve during gas delivery and gas purging. Thiscontrols the flow of gas through apertures (seen, for example, in FIG.4) spaced along the length of the channel.

The cross-sectional shape of the delivery channel 102 can be controlledsuch that gas flowing through the delivery channel experiences minimalresistance to flow. In some embodiments, the delivery channel 102 has around or oval cross-sectional shape. In one or more embodiments, thedelivery channel 102 has a cross-sectional shape sufficient such thatbends, turns, twists, etc. provide substantially no dead space.

The overall shape (as opposed to the cross-sectional shape) of thedelivery channel 102 can be modified as desired. For example, thedelivery channel 102 can be shaped to fit within specific areas or tomatch the shape of a substrate. The delivery channel 102 can be, forexample, straight, round, square, oval, rectangular or oblong.Additionally, the overall shape of the delivery channel can be made upof repeating units, which are parallel, perpendicular or concentric toeach other. In one or more embodiments, the delivery channel has anoverall shape in which there is substantially no dead space to inhibitgas flow or purging. As used in this specification and the appendedclaims, the term “substantially no dead space” means that the flow ofgas, or purging, is inhibited by less than about 10% or by less thanabout 5% due to dead space.

In some embodiments, the delivery channel 102 is a tubular spiral havinga substantially planar configuration. This particular shape isexemplified by the embodiment shown in FIGS. 1 and 2. As used in thisspecification and the appended claims, the term “substantially planarconfiguration” means that the plurality of apertures 108 in the deliverychannel 102 are in mostly the same plane. The embodiment shown in FIGS.1 and 2 has a substantially planar configuration because the aperturesare coplanar, even though the inlet end and outlet end, and the portionsof the delivery channel near the inlet end and outlet end are notcoplanar with the plurality of apertures.

The delivery channel 102 can be used for plasma processing. For example,the delivery channel 102 can be polarized relative to another portion ofthe processing chamber to ignite a plasma within the chamber. Thedelivery channel 102 can be biased relative to a portion of the chamber,or a portion of the chamber can be biased relative to the deliverychannel 102. For example, the delivery channel 102 can be polarizedrelative to the pedestal, or the pedestal can be polarized relative tothe delivery channel. The frequency of the plasma can be tuned as well.In one or more embodiments, the plasma is at a frequency of about 13.56MHz. In some embodiments, the plasma is at a frequency of about 40 MHz,50 MHz, 60 MHz, 70 MHz, 80 MHz, 90 MHz, 100 MHz, 110 MHz or 120 MHz.

Any suitable material can be used for the delivery channel, showerheador gas distribution apparatus. Suitable materials include, but are notlimited to stainless steel and inert materials. In some embodiments, thedelivery channel, showerhead or gas distribution plate is made ofstainless steel.

FIG. 3 shows a cross-section of a portion of a processing chamberaccording to one or more embodiments. A gas distribution apparatus 100is placed between a substrate support 302 and a gas distribution plate306. The substrate support 302 is shown supporting a substrate 304. Thesubstrate support 302 can be stationary or rotating, or can bestationary for part of the processing and rotating for part of theprocessing. A rotating substrate support 302 may allow for more uniformprocessing of a substrate by minimizing different gas flow patterns thatmay occur throughout the processing chamber. The substrate support 302of some embodiments includes a heater or heating mechanism. The heatercan be any suitable type of heater including resistive heaters.

The gas distribution apparatus 100 is shown as a tubular spiral with asubstantially planar configuration. The substrate 304 can be processedwith either, or both, the gas distribution plate 306 and the gasdistribution apparatus 100. The gas distribution apparatus 100 can beshaped so that it does not substantially interfere with gas flowing fromthe gas distribution plate 306. As used in this specification and theappended claims, the term “substantially interfere” means that the gasdistribution apparatus 100 does not interfere with more than about 30%of the gas flowing from the gas distribution plate. For example, thefront surface 308 of the gas distribution plate 306 has a plurality ofapertures 310 through which gases flow. The gas distribution apparatus100 can be shaped to avoid blocking the apertures 310.

The delivery channel positioned like that of FIG. 3 can also be used forplasma processing. The apparatus 100 can be polarized relative to aportion of the chamber, or a portion of the chamber can be polarizedrelative to the apparatus 100. For example, the delivery channelapparatus 100 can be polarized relative to the substrate support 302, orthe substrate support 302 can be polarized relative to the apparatus100. In some embodiments, the apparatus 100 is polarized relative to thegas distribution plate 306. In one or more embodiments, the gasdistribution plate 306 is polarized relative to the substrate support302 and gas flowing from the apparatus 100 forms the plasma. Thefrequency of the plasma can be tuned as well. In one or moreembodiments, the plasma is at a frequency of about 13.56 MHz. In someembodiments, the plasma is at a frequency of about 40 MHz, 50 MHz, 60MHz, 70 MHz, 80 MHz, 90 MHz, 100 MHz, 110 MHz or 120 MHz.

FIGS. 4 through 7 show another embodiment of a gas distributionapparatus 400 in which the delivery channel 402 is a recessed channel inthe back side 401 of a gas distribution plate 403. The embodiment shownhas a large inner section recessed in the back side 401 of the gasdistribution plate 403 with the delivery channel 402 recessed evenfurther. This allows for the addition of a back cover 407 which can beplaced in the recessed area in the back side 401 enclosing the deliverychannel 402. The back cover 407, when inserted into the recessed backside 401 of certain embodiments creates a substantially flush back sidesurface of the gas distribution plate. It will be understood by thoseskilled in the art that the back cover 407 does not need to fit within arecessed area of the back side 401 of the gas distribution plate 403,but can also rest directly on the back side 401 of the gas distributionplate 403. In embodiments of this sort, there is no large recessed areawith the delivery channels being further recessed. Instead, the deliverychannels are recessed directly into the back side 401 of the gasdistribution plate 403.

The back cover 407 may have openings to allow for the passage of inletand outlet tubes to allow for fluid communication with the deliverychannel 402. This can be seen in FIGS. 5 and 6. The inlet and outlettubes can be an integral part of the back cover 407, or can be separatepieces connected to the back cover 407 in such a manner as to prevent orminimize fluid leakage. A plurality of apertures 408 extend through thegas distribution plate 403 to a front side 405 of the gas distributionplate 403. These apertures can be seen in FIGS. 4, 5 and 7. Theplurality of apertures 408 can be evenly spaced along the length of thedelivery channel, or can have varied spacing along the length of thechannel. Variable spacing may help produce a more uniform gas flow fromthe delivery channel at points along the delivery channel. For example,in gas delivery channel that has an elaborate shape, the spacing of theapertures can varied along the length.

In the embodiment shown in FIGS. 4-7, the gas distribution plate 403 isround and the delivery channel 402 forms a spiral shape. The inlet end404 is denoted at the outside of the spiral in an outer peripheralregion 420 of the gas distribution plate 403 with the outlet end 406 atthe center of the spiral in a central region 422 of the gas distributionplate 403. It will be understood by those skilled in the art that theinlet end 404 and outlet end 406 can be reversed with the inlet end 404being located at the center of the spiral and the outlet end 406 at theoutside of the spiral. In some embodiments, one of the inlet end 404 andoutlet end 406 is positioned in an outer peripheral region 420 of thegas distribution plate 403 and the other of the inlet end 404 and outletend 406 is positioned in a central region 422 of the gas distributionplate 403. In one or more embodiments, the inlet end 404 is positionedat the outer peripheral region 420 of the gas distribution plate 403 andthe outlet end 406 is positioned at the central region 422 of the gasdistribution plate 403. In certain embodiments, the outlet end 406 ispositioned at the outer peripheral region 420 of the gas distributionplate 403 and the inlet end 404 is positioned at the central region 422of the gas distribution plate 403.

In FIGS. 5 and 6, the inlet end 404 and outlet end 406 are illustratedas a small tube extending from the back cover 407 of the gasdistribution plate 403. The tubes extend between the inlet 410 and theback cover 407 through an inlet valve 414. Another tube can extendbetween the outlet 412 and the back cover 407 through the outlet valve416. The tubes can be connected to the back cover 407 by any suitableconnection known to those skilled in the art and may be sealed toprevent leakage of fluid flowing through the tube into the deliverychannel 402. Suitable sealing devices include, but are not limited to,o-rings positioned between a flange 424 and the back cover 407. Theflange 424 can be integrally formed with the tube or can be a separatepiece that holds the tube to the back cover. The flange 424 can beconnected to the back cover 407 by any suitable mechanical connection,including but not limited to, screws.

FIG. 8A shows a cross-sectional view of one portion of a deliverychannel 402 and an aperture 408 in a gas distribution plate 403 inaccordance with one or more embodiments of the disclosure. It will beunderstood by those skilled in the art that the delivery channel andapertures described in FIG. 8A are merely illustrative and should not betaken as limiting the scope of the disclosure. Those skilled in the artwill understand that there are other ways of creating flow from thedelivery channel 402 through the gas distribution plate 403. Thedelivery channel 402 shown in FIG. 8A has two portions, an upper portion832 and a lower portion 830. While these portions are shown as separateareas, it will be understood that there can be a seamless transitionbetween the upper portion 832 and the rounded lower portion 830.

Additionally, it will be understood that the upper portion 832 isoptional and does not need to be included in the delivery channel 402.When there is no upper portion 832, the lower portion 830 is the onlyportion. Thus, the delivery channel can have any suitable shape. In someembodiments, the shape of the delivery channel is such that there issubstantially no interference with the flow of gases through thechannel.

The upper portion 832 can have any suitable shape. In the embodimentshown in FIG. 8A, the upper portion 832 has walls which extend normal tothe surface of the back side 401 of the gas distribution plate 403.However, it will be understood that the upper portion 832 can have wallswhich are canted from square to the back side 401. The canting canprovide a larger opening at the back side 401 of the gas distributionplate 403, tapering to a smaller opening. Additionally, the canting canprovide a smaller opening at the back side 401, tapering to a largeropening. The length of the upper portion 832 can be modified asnecessary.

In some embodiments, the upper portion has sides which are substantiallyperpendicular to the back side 401 of the gas distribution plate 403 andextend a length L below the surface of the back side 401 in the range ofabout 0.01 inch to about 0.3 inches. As used in this specification andthe appended claims, the term “substantially perpendicular to” meansthat walls of the upper portion have an angle relative to the back sideof the gas distribution plate in the range of about 85 degrees to about95 degrees. In some embodiments, the upper portion extends below thesurface of the back side to a length L in the range of about 0.02 inchesto about 0.2 inches, or in the range of about 0.05 inches to about 0.15inches, or in the range of about 0.08 inches to about 0.12 inches. Inone or more embodiments, the upper portion extends below the surface ofthe back side to a length about 0.1 inches.

The rounded lower portion 830 can have any suitable cross-sectionincluding, but not limited to, half-round and half-elliptical. The widthof the rounded lower portion, also referred to as the diameter of therounded lower portion, can be modified as necessary. The width of theupper portion can be modified as necessary. The diameter of the deliverychannel, in general, can have an impact of the number of loops in thespiral. In some embodiments, as shown in FIG. 8A, the width of the upperportion is about equal to the diameter of the lower portion. Thedelivery channel of various embodiments has a diameter in the range ofabout 0.3 inches to about 0.45 inches, or in the range of about 0.325inches to about 0.425 inches, or in the range of about 0.35 inches toabout 0.40 inches. In one or more embodiments, the delivery channel hasa diameter of about 0.375 inches.

The specific shape of the apertures 408 can vary depending on thedesired flow of gases through the apertures. In the embodiment of FIG.8A, the aperture 408 has three distinct sections; a first section 834, asecond section 836 and a third section 838. Again, the number ofsections and the shape of the sections are merely illustrative of oneembodiment and should not be taken as limiting the scope of thedisclosure. The first section 834 extends from the rounded lower portion830 of the delivery channel 402 toward the front side 405 of the gasdistribution plate 403. The first section 834 has a first diameter D1.The second section 836 extends from the first section 834 toward thefront side 405 and has a diameter which tapers from the first diameterD1 to a second diameter D2, which is generally smaller than the firstdiameter. The third section 838 extends from the end of the secondsection 836 and ends at the front side 405 of the gas distribution plate403. At the intersection of the third section 838 and the front side405, a hole 840 is formed. Gases flowing through the delivery channel402 exit the gas distribution plate 403 through this hole 840 into theprocessing chamber. The hole 840 has about the same diameter as thesecond diameter D2. In various embodiments, the diameter of hole 840 isin the range of about 0.01 inches to about 0.25 inches, or in the rangeof about 0.02 inches to about 0.2 inches, or in the range of about 0.03inches to about 0.15 inches or in the range of about 0.04 inches toabout 0.1 inches. In some embodiments, the hold 840 has a diameter lessthan about 0.1 inches, or less than about 0.08 inches, or less thanabout 0.06 inches, or less than about 0.04 inches, or less than about0.02 inches, or less than about 0.01 inch.

As the delivery channel spirals from the outer peripheral edge of thegas distribution plate to the central region, or vice versa, a seemingplurality of adjacent channels are observable in cross-section, eventhough it may be a single channel. FIG. 5 shows this seeming pluralityof channels. The channels, or separation between loops of the spiral,are separated by a distance. In some embodiments, the distance betweenthe channels, or the loops of the single channel, measured from centers,are in the range of about 0.375 inches to about 0.475 inches, or in therange of about 0.40 inches to about 0.45 inches, or in the range ofabout 0.41 inches to about 0.43 inches. In one or more embodiments, theaverage distance between centers of the adjacent channels is about 0.42inches.

The length of the gas channel shown in FIGS. 4 to 7 can vary dependingon a number of factors, including, but not limited to, the diameter ofthe channel and the distance between the adjacent channels. In variousembodiments, the delivery channel has a length in the range of about 140inches to about 340 inches, or in the range of about 180 inches to about300 inches, or in the range of about 200 inches to about 280 inches, orin the range of about 220 inches to about 260 inches. In one or moreembodiments, the delivery channel has a length of about 240 inches.

The number of apertures is also dependent on a variety of factors,including but not limited to, the length of the delivery channel and thespacing of the apertures. In some embodiments having a single spiralchannel, there are in the range of about 300 and 900 apertures, or inthe range of about 400 to about 800 apertures, or in the range of about500 to about 700 apertures. In various embodiments, there are greaterthan about 300, 400, 500, 600, 700 or 800 apertures along the length ofthe channel. In one or more embodiments, there are about 600 aperturesalong the length of the delivery channel.

In some embodiments, each of the plurality of apertures 408 has anindependent hole diameter and delivery angle relative to the front side405 of the gas distribution plate. The plurality of apertures 403 mayhave one or more of (1) variable spacing along the length of thedelivery channel; (2) variable hole diameters along the length of thedelivery channel; and (3) variable delivery angles along the length ofthe channel.

In some embodiments, the spacing between apertures vary depending on theexpected gas pressure in any particular region of the channel. Forexample, the gas pressure across the length of the channel will changedue to, for example, the presence of apertures allowing gas to escapethe channel. To counteract this pressure variability, there can be anincrease or decrease in the density of apertures. The regions of thechannel can be any length from the entire channel length to lengths lessthan the diameter of the apertures. For example, the first half of thechannel length can have apertures spaced a first amount and the nextquarter have apertures spaced closer together (i.e., a greater densityof apertures) with the last quarter being even greater density. In someembodiments, the spacing of the plurality of apertures decreases alongthe length of the delivery channel from the inlet end to the outlet end.The decreasing spaces can be between each channel or between blocks ofchannels.

For example, FIG. 8H shows a linear channel with three sections. A gasflowing from left-to-right would pass through the first section whichtakes ½ the channel length and then each of the next two sections whichtake about ¼ the length of the channel each. The spacing of theapertures 808 in the first section is larger than the spacing in thesecond section which is, in turn, larger than the spacing the lastsection. Here, the density of apertures changes in blocks or sections.The first section has the smallest density of (i.e., largest spacingbetween) apertures. The spacing between each of the apertures in thefirst section is the same. The spacing between each of the apertures inthe second section are smaller than the first section. The spacingbetween each of the apertures in the second section is the same. Thespacing between each of the apertures in the third section is thesmallest with the spacing between each of these apertures the same.

FIG. 8I shows an example of a spiral gas delivery channel 802 withgradually decreasing spaces between apertures 808. Here, the spacingbetween apertures is greatest at the inlet end with decreasing spacingtoward the center of the spiral, which in this case, is the outlet end.It can also be seen that near the center of the spiral, the aperturesare not only spaced close together along the length of the channel, butalso spaced close together across the width of the spiral so that theapertures initially occur singly at any particular distance from theinlet end to multiple apertures at any particular distance from theinlet end.

In some embodiments, the diameter of the individual apertures can changealong the length of the channel. As the gas pressure in the deliverychannel decreases along the length of the channel, the diameter of theapertures can increase. FIG. 8J shows an example of a gas deliverychannel 802 with gas flowing from left-to-right. The diameter of theapertures 808 gradually increase along the length of the channel withthe largest diameter at the outlet end. The hole diameters are shownincreasing gradually, but these could also change in blocks or segments,like the spacing described above.

The apertures can have any number of possible cross-sections. FIGS. 8Athrough 8G show a number of possible cross-sections. The apertures canbe a single straight line that leads from the channel to the front side,or can have a number of sections. The number of sections and shapes canhave an impact on the spray pattern of gases exiting the gas deliverychannel through the apertures. In some embodiments, the aperturescomprise a first section 834 having a first diameter and a secondsection 836 having a second diameter which is different from the firstdiameter. FIG. 8B shows an aperture 808 with a first section 834adjacent the gas delivery channel and extending toward the front side405. The second section 836 has a changing diameter which increases fromthe end closest the first section 834 toward the front side 405. Stateddifferently, the second diameter transitions from the first diameter tothe second diameter. A third section 838 connects the second section 836to the front side 405. The diameter of the third section 838 is thesecond diameter.

As shown in comparing FIGS. 8A and 8B, the first diameter can be largerthan or smaller than the second diameter. In FIG. 8A, the first diameteris larger than the second diameter and in FIG. 8B, the reverse is thecase.

FIGS. 8C and 8D show embodiments of the apertures which include a fourthsection 839. In FIG. 8C, the first section 834 has a first diameter, thesecond section 836 transitions from the first diameter to a seconddiameter, the third section extends from the second section 836 towardthe front side 405. A fourth section 839 extends from the third section838 to the front side 405 with a varying size diameter. The fourthsection 839 diameter increases from the second diameter to a thirddiameter at the front side 405 so that the hole 840 is larger than thesecond diameter. The third diameter can be the same as or different fromthe first diameter and is different from the second diameter. FIG. 8Dshows a similar situation in which the first diameter and seconddiameter are reversed. The size of the hole 840 and the angle of thefourth section 839 can vary and may impact the gas spray pattern. FIG.8E shows another embodiment in which there are two sections. The firstsection 834 extends from the gas delivery channel and has a firstdiameter. The second section 836 extends from the first section 834 tothe front side 405 and has a diameter starting at the first diameter andtransitioning gradually to the second diameter. While the seconddiameter shown is larger than the first diameter, it could also besmaller than the first diameter. The embodiments shown are merelyexemplary and should not be taken as limiting the scope of thedisclosure.

The width W of the gas delivery channels 402 and the pattern/number ofapertures 408 across the width W of the gas delivery channels can alsovary. FIG. 8F shows a cross-section of a portion of a gas distributionplate with two adjacent channels. The left channel has a width W muchlarger than the right channel. Additionally, the left channel has threeseparate apertures 408 extending in a line across the width of thechannel. Stated differently, there are three apertures in the channel atthe same distance from the inlet end. This means that the plurality ofapertures extend along the length of the channel and may also extendalong the wide of the channel. The two channels shown in FIG. 8F can beseparate portions of the same channel (e.g., adjacent channels of aspiral shape). The diameter of the channel can increase or decreasealong the length of the channel to change the gas flow pattern throughthe channel. The two channels shown in FIG. 8F can also be from separatechannels with different gases flowing therethrough. For example, the gasflowing through the wider left channel may not be as reactive as the gasflowing through the narrower right channel, and the amount of the leftgas exiting the channel is greater than the amount of the right gas.Again, these are merely examples of possible arrangements and should notbe taken as limiting the scope of the disclosure. The gas distributionapparatus of claim 1, wherein some of the plurality of aperturescomprise a plurality of passages forming a line extending across a widthof the delivery channel.

In some embodiments, the individual apertures extend toward the frontside 405 at varying angles from the gas delivery channel. The aperturescan also have variable delivery angles relative to the front side of thegas distribution plate. FIG. 8G shows an embodiment of the disclosure inwhich there are two adjacent channels with three apertures extendingacross the width of each. The channels can be delivering the same gas oradjacent channels delivering different gases. Of the three channels, oneextends straight down from the channel to make an angle about 90°, theside channels extend at an angle and make an angle θ relative to thefront side of the gas distribution plate. The angle can be any suitableangle in the range of about 10° to about 90°. In one or moreembodiments, the angle is in the range of about 20° to about 85°, or inthe range of about 30° to about 80°, or in the range of about 40° toabout 75°. In some embodiments, as can be extrapolated from the channelsof FIG. 8G, at least some of the pluralities of apertures have deliveryangles that direct a flow of gas toward a region under an adjacentdelivery channel. This can help with uniformity of the deposition byminimizing striping caused by shape of the channel.

In an embodiment, as shown in FIG. 4, the gas delivery plate 403comprises a single delivery channel 402 in a back side of the gasdelivery plate 403. The delivery channel 402 has an inlet end 404located in an outer peripheral region 420 of the gas distribution plate403. The delivery channel 402 follows an inward spiral path from theinlet end 404 to an outlet end 406 located in a central region 422 ofthe gas distribution plate 403. The delivery channel 402 has an overalllength, defined as the distance between the inlet end 404 and the outletend 406 of about 240 inches. A plurality of apertures 408 are spacedalong the overall length of the delivery channel 402. Along the overalllength of the delivery channel 402 there are in the range of about 500apertures and about 700 apertures. The delivery channel 402 has anaverage diameter of about 0.375 inches and adjacent portions of thespiral channel are spaced about 0.42 inches on center.

Some embodiments of the disclosure include more than one deliverychannel 402. These multiple channels can be intertwined or separatedepending on the needs of the processing system. Some channels can berecessed into a gas distribution plate as shown in FIG. 4, or can beindividual tubes as shown in FIG. 1. In some embodiments, there are acombination of individual tubes and recessed channels. An exemplaryembodiment of the sort is shown in FIG. 3, where the gas distributionplate may have at least one recessed delivery channel therein and anadditional delivery channel is positioned between the gas distributionplate and the substrate surface.

Another embodiment of the disclosure is shown in FIGS. 9 through 14. Agas distribution apparatus 900 comprises two delivery channels 902 a,902 b recessed in the back side 901 of a gas distribution plate 903. Itwill be understood that the delivery channels do not need to be recessedinto the back of a gas distribution plate, but can be individual tubes,as shown in FIGS. 1 and 15. The first delivery channel 902 a has a firstinlet end 904 a and a first outlet end 906 a and a plurality of firstapertures 1908 a spaced along the length of the first delivery channel902 a. The second delivery channel 902 b has a second inlet end 904 b, asecond outlet end 906 b and a plurality of second apertures 1908 bspaced along the length of the second delivery channel 902 b.

A first inlet 910 a is connected to the first inlet end 904 a of thefirst delivery channel 902 a. The first inlet 910 a is adapted to beconnected to a gas source. A first outlet 912 a is connected to thefirst outlet end 906 a of the first delivery channel 902 a. The firstoutlet 912 a is adapted to be connected to a vacuum source. A secondinlet 910 b is connected to the second inlet end 904 b of the seconddelivery channel 902 b. The second inlet 910 b is adapted to beconnected to a gas source. A second outlet 912 b is connected to thesecond outlet end 906 b of the second delivery channel 902 b. The secondoutlet 912 a is adapted to be connected to a vacuum source.

In the embodiment shown in FIGS. 9 to 14, each of the delivery channels902 a, 902 b form a spiral shape. One or more embodiments, as that shownin the Figures, have the two delivery channels 902 a, 902 b intertwinedalong the length of the spiral shape. It will be understood by thoseskilled in the art that the two delivery channels 902 a, 902 b can haveshapes other than spiral and do not need to intertwine. In certainembodiments, the plurality of first apertures 1908 a and secondapertures 1908 b extend through the gas distribution plate 903 to thefront side 905 of the gas distribution plate 903.

In some embodiments, each of the delivery channels 902 a, 902 b form aspiral shape with one of the inlet end 904 a, 904 b and outlet end 906a, 906 b positioned in an outer peripheral region 920 of the gasdistribution plate 903 and the other of the inlet end 904 a, 904 b andoutlet end 906 a, 906 b positioned in a central region 922 of the gasdistribution plate 903. In one or more embodiments, the inlet ends 904a, 904 b of both channels 902 a, 902 b is positioned in the outerperipheral region 920 and the inlet ends 904 a, 904 b of both channels902 a, 902 b are positioned in the central region 922 of the gasdistribution plate 903. In certain embodiments, the inlet ends 904 a,904 b of both channels 902 a, 902 b is positioned in the central region922 and the inlet ends 904 a, 904 b of both channels 902 a, 902 b arepositioned in the outer peripheral region 920 of the gas distributionplate 903. In one or more embodiments, one of the inlet ends 904 a, 904b is positioned in the outer peripheral region 920 and the other inletend 904 b, 904 a is positioned at the central region 922, with theoutlet ends 906 a, 906 b at the other end of each individual deliverychannel 902 a, 902 b.

FIG. 10A shows a cross-sectional view of a gas distribution plate withtwo gas delivery channels. The shape, number, spacing and angles of theapertures can vary, as previously described. FIG. 10B shows a portion ofan embodiment of a gas distribution plate with a first delivery channel902 a and a second delivery channel 902 b. Both of these channels 902 a,902 b, at least at the cross-section shown, have two apertures extendingfrom the channel to the front side 905 of the gas distribution plate.The apertures shown are positioned at the outer edges of the channels sothat the gases in the channels are very close to each other when exitingthe apertures. The apertures between the first channel and the secondchannel can also be offset so that only one channel would have aperturesvisible in any given cross-section to prevent gas phase reactions.

FIG. 10C shows another embodiment in which there are two gas channelswith each channel having two apertures extending therefrom to form adelivery angle at the front side 905. Here, neither channel is shownwith an aperture that expels gas directly below that aperture, butinstead directs gases to the region beneath an adjacent channel. Thefirst delivery channel 902 a has an aperture that directs gas beneaththe second delivery channel 902 b and the second delivery channel 902 bhas an aperture that directs gas beneath the first delivery channel 902a. These apertures are shown to form holes at the same point on thefront side, but it will be understood that these can be staggered alongthe length of the channel or that the cross-section shown for eachchannel can be from a different length from the inlets.

The embodiment of FIG. 10C may be particularly effective at preventingdeposition striping from the placement and orientation of the gases.FIG. 10D shows the surface of a portion of a gas distribution plate inwhich the channels have apertures like that of FIG. 10C which haveoffset cross-sections. The pattern of holes on the front side 905presents an approximately alternating pattern of holes.

FIG. 11 shows a back cover 907 for the gas distribution plate 903 shownin FIG. 9. There are four holes (not numbered) located in the back cover907 which align approximately with the inlet ends 904 a, 904 b andoutlet ends 906 a, 906 b of the delivery channels 902 a, 902 b. Theholes can be used to provide an access point for connected in the inlet910 a, 910 b and outlet 912 a, 912 b to the channels 902 a, 902 b. Insome embodiments, there inlet 910 a, 910 b and outlet 912 a, 912 b areintegrally formed with the back cover 907. Additionally, as seen inFIGS. 12 and 13, there can be one or more inlet valves 914 a, 914 b andoutlet valves 916 a, 916 b

FIGS. 12 and 13 show perspective views of a gas distribution apparatus900 in accordance with various embodiments of the disclosure. The inlets910 a, 910 b are shown connected to the back cover 907 with a flange 924a, 924 b. The connection and gas-tight sealing of the flange 924 a, 924b can be accomplished by any suitable mechanism and techniques as knownto those skilled in the art. The outlets 912 a, 912 b can also beconnected to the back cover 907 with a flange or with a blockconnection. The block 925 can be integrally formed with the back cover907 or can be a separate piece. The block 925 may provide additionalsupport and space for the outlet valves 916 a, 916 b, allowing theconnecting tubes to protrude from the back cover 907 at an angle.Although the inlets 910 a, 910 b and inlet valves 914 a, 914 b are shownon the outside peripheral region 920 of the gas distribution plate 903and the outlets 912 a, 912 b and outlet valves 916 a, 916 b are shown atthe central region 922 of the gas distribution plate 903, it will beunderstood that these components can be reversed or intermixed and thatthe drawings are merely illustrative of one embodiment.

As the delivery channels spiral from the outer peripheral edge of thegas distribution plate to the central region, or vice versa, a seemingplurality of adjacent channels are observable in cross-section. With thespirals intertwined, the gas in every adjacent channel is from the otherinlet 910 a, 910 b. The channels are separated by a distance from theadjacent channels. In some embodiments, the distance between thechannels, measured from the center of the channel, are in the range ofabout 0.375 inches to about 0.475 inches, or in the range of about 0.40inches to about 0.45 inches, or in the range of about 0.41 inches toabout 0.43 inches. In one or more embodiments, the average distancebetween centers of the adjacent channels is about 0.42 inches.

The length of the gas channel shown in FIGS. 9-14 can vary depending ona number of factors, including, but not limited to, the diameter of thechannel and the distance between the adjacent channels. In variousembodiments, each of the delivery channels has a length in the range ofabout 70 inches to about 170 inches, or in the range of about 90 inchesto about 150 inches, or in the range of about 100 inches to about 140inches, or in the range of about 110 inches to about 130 inches. In oneor more embodiments, the delivery channel has a length of about 120inches.

The number of apertures are also dependent on a number of factors,including but not limited to, the length of the delivery channel and thespacing of the apertures. In some embodiments having a single spiralchannel, there are in the range of about 150 and 450 apertures, or inthe range of about 200 to about 400 apertures, or in the range of about250 to about 350 apertures. In various embodiments, there are greaterthan about 150, 200, 250, 300, 350 or 400 apertures along the length ofthe channel. In one or more embodiments, there are about 300 aperturesalong the length of each of the delivery channels.

The apparatus shown in FIGS. 4 through 14 can be used for plasmaprocessing. For example, the delivery channel, gas distributionapparatus or showerhead can be polarized relative to another portion ofthe processing chamber to ignite a plasma within the chamber. Thedelivery channel, gas distribution apparatus or showerhead can bepolarized relative to a portion of the chamber, or a portion of thechamber can be biased relative to the delivery channel, gas distributionapparatus or showerhead. For example, the delivery channel, gasdistribution apparatus or showerhead can be polarized relative to thepedestal, or the pedestal can be polarized relative to the deliverychannel, gas distribution apparatus or showerhead. The frequency of theplasma can be tuned as well. In one or more embodiments, the plasma isat a frequency of about 13.56 MHz. In some embodiments, the plasma is ata frequency of about 40 MHz, 50 MHz, 60 MHz, 70 MHz, 80 MHz, 90 MHz, 100MHz, 110 MHz or 120 MHz.

In some embodiments of the apparatus exemplified by FIGS. 4 through 14,there is an insulating material (not shown) positioned between the backcover and the main body portion of the gas distribution apparatus (i.e.,the portion including the gas delivery channel). This insulatingmaterial provides electrical isolation between the back cover and themain body portion of the gas distribution apparatus so that the backcover can be polarized relative to the main body portion. Doing so mayallow for the ignition of a plasma within the gas distributionapparatus, or within the delivery channels. The plasma can then beflowed through the plurality of apertures into the processing region ofthe processing chamber, the processing region being the region betweenthe gas distribution apparatus and the pedestal. This configuration maybe referred to as a remote plasma because the plasma is formed (e.g.,ignited) outside of the processing region.

FIGS. 15, 16A and 16B show another exemplary embodiment of a gasdistribution apparatus 1500. The gas distribution apparatuses shown areparticularly useful for spatially separated atomic layer depositionprocesses in which different portions of the substrate aresimultaneously exposed to different deposition gases and the substrate1544 is moved relative to the gas distribution apparatus so that allparts of the substrate are exposed sequentially to each of thedeposition gases. In these embodiments, the gas distribution apparatus1500 comprises a plurality of delivery channels 1502, each deliverychannel 1502 extending substantially straight and substantially parallelto adjacent delivery channels. Each of the delivery channels 1502 has aninlet end 1504 and an outlet end 1506 with a plurality of spacedapertures 1508 there between.

The gas distribution apparatus shown in FIGS. 15, 16A and 16B have aplurality of elongate delivery channels 1502 and a plurality of elongatevacuum channels 1550. Each of the delivery channels 1502 and vacuumchannels 1550 are connected to a output channel 1552 at the front sideof the gas distribution apparatus. Each of the delivery channels 1502 isadapted to flow one or more of a reactive gas and a purge gas. Eachdelivery channel 1502 is connected to an output channel 1552 by aplurality of spaced apertures 1508. Each of the vacuum channels 1550 isconnected to an inlet channel 1554 by a plurality of spaced vacuumapertures 1558. The plurality of apertures 1508 of each delivery channel1502 are separated from the plurality of apertures 1508 of each adjacentdelivery channel 1502 by at least one of the plurality of vacuumapertures 1558 from a vacuum channel 1550.

In the embodiment shown in FIG. 16A, each of the central vacuum channels1550 (not the end vacuum channels) are connected to two inlet channels1554 by vacuum apertures 1508. The end vacuum channels 1550 are onlyconnected to a single inlet channel 1554. It should be understood thatthis is merely exemplary and should not be taken as limiting the scopeof the disclosure. Each inlet channel 1554 can have a dedicated vacuumchannel 1550, or a single vacuum channel 1550 can be connected to morethan two inlet channels 1554 through a plurality of vacuum apertures1508.

While each of the delivery channels appears the same, there can be adifferent gas flowing through each. For example, purge channels (denotedP) may have a purge gas flowing there through, each of the firstreactive gas channels (denoted A) may have a first reactive gas flowingthere through and each of the second reactive gas channels (denoted B)may have a second reactive gas flowing there through. The vacuumchannels (denoted V) are connected to a vacuum source. With reference toFIG. 16A, a substrate 1544 (or more specifically, a fixed point on asubstrate) moving from left to right would encounter in order a vacuumgas channel, a purge gas channel, a vacuum gas channel, a first reactivegas channel, a vacuum gas channel, a purge gas channel, a vacuum gaschannel, a second reactive gas channel, a vacuum gas channel, etc.,depending on the size of the gas distribution plate.

The use of the delivery channels with inlet and outlet ends allows forthe rapid exchange of gas within the delivery channel. For example,after the substrate (or fixed point on the substrate) is exposed to thesecond reactive gas channel (denoted B), the outlet end of the deliverychannel can be opened, allowing the gas within the channel to beremoved, and a different reactive gas (e.g., gas C) can then be flowedinto the delivery channel. Thus, when the substrate passes back underthat gas channel the substrate will be exposed to gas C instead of gasB. While this example has been made with respect to a second reactivegas, it will be understood by those skilled in the art that one of thegas delivery channels (first reactive gas, second reactive gas or purgegas) can be purged and replaced with a different gas.

The delivery channel of FIGS. 15, 16A and 16B can be used for plasmaprocessing as well. The gas distribution apparatus 1500 can be biasedrelative to another portion of the chamber. For example, the gasdistribution apparatus 1500 can be polarized relative to the pedestal,or the pedestal can be polarized relative to the gas distributionapparatus. The frequency of the plasma can be tuned as well. In one ormore embodiments, the plasma is at a frequency of about 13.56 MHz. Insome embodiments, the plasma is at a frequency of about 40 MHz, 50 MHz,60 MHz, 70 MHz, 80 MHz, 90 MHz, 100 MHz, 110 MHz or 120 MHz.

FIG. 16B shows an embodiment of a single delivery channel 1502 and asingle vacuum channel 1550. Each of the delivery channel 1502 and vacuumchannel 1550 have two sets of apertures extending therefrom. In the caseof the vacuum channel 1550, one set of apertures 1558 a connect to afirst inlet channel 1554 a and the other set of apertures 1558 bconnects to a second inlet channel 1554 b. The delivery channel 1502, onthe other hand, has two sets of apertures 1508 extending to a singleoutput channel 1552.

In one or more embodiments, the gas distribution apparatus includes morethan one outlet connected to a vacuum source. FIG. 17 shows a spiralshaped gas distribution apparatus 1700 which is similar to the apparatus100 shown in FIG. 1. The apparatus includes a delivery channel 1702 withan inlet end 1704 and an outlet end 1706. An inlet 1710 is connected toand in communication with the inlet end 1704 of the delivery channel1702. An outlet 1712 is connected to and in communication with theoutlet end 1706 of the delivery channel 1702. The inlet 1710 isconnectable to a gas source and may include an inlet valve 1714 that cancontrol the flow of gas into (or out of) the delivery channel 1702 orcompletely cut off the flow of gas. The outlet 1712 is connectable to avacuum source (not shown) and may include an outlet valve 1716 that cancontrol the flow of gas out of (or into) the delivery channel 1702 orcompletely cut off the vacuum source from the delivery channel 1702. Anintermediate outlet 1742 which is connectable to the vacuum source (notshown) is position along the length of the delivery channel 1702. Theintermediate outlet 1742 shown is connected to the delivery channel 1702at about the middle of the length of the channel 1702 and coupled to thedelivery channel 1702 through an intermediate outlet 1740. Theintermediate outlet 1742 may include an intermediate outlet valve 1744that can control the flow of gas out of (or into) the delivery channel1702 or completely cut off the vacuum source from the delivery channel1702. The inlet valve 1714 of the inlet 1710, the outlet valve 1716 ofthe outlet 1712 and the intermediate outlet valve 1744 of theintermediate outlet 1740 are connected to a controller 1750. Thecontroller is capable of independently opening or closing any or all ofthe valves to adjust the pressure of gases flowing through the deliverychannel 1702 or purge the delivery channel 1702 of an existing gas. Forexample, Table 2 shows a processing sequence that may be used with theembodiment shown in FIG. 17. It will be understood by those skilled inthe art that this is merely an example and should not be taken aslimiting the scope of the disclosure.

TABLE 2 Intermediate Step Gas Source Outlet valve Outlet valve 1aPrecursor A Closed Partially Open 1b Precursor A Closed Closed 2a PurgeOpen Closed 2b Purge Open Open 2c Purge Open Closed 3a Precursor BPartially Open Closed 3b Precursor B Closed Closed

The valves shown in Table 2 are open, closed or partially open at anypoint during the processing. In Step 3 a, after purging the deliverychannel of Precursor A, the intermediate outlet valve is partially opento accelerate the flow of Precursor B through the delivery channel andthen closed in Step 3 b. This is merely one possible sequence that canbe used and should not be taken as limiting the scope of the disclosure.

The embodiment shown in FIG. 17 effectively includes two outlets, one atthe end of the delivery channel and one in the middle. Those skilled inthe art will understand that there can be any number of outlets spacedalong the length of the delivery channel and at any position along thelength of the channel. For example, the intermediate outlet 1740 couldbe positioned at ⅓ of the length of the channel. Additionally, there canbe any number of outlets. For example, the delivery channel may havefour outlets, one at the end and one positioned at each of ¼, ½ and ¾ ofthe length of the delivery channel. In another example, the deliverychannel includes four outlets, one at the end and one position at eachof ¼, ¾ and 9/10 of the length of the delivery channel. In someembodiments, the delivery channel includes 2, 3, 4, 5, 6, 7, 8, 9, 10 or11 total outlets (including an outlet at the outlet end of the channel).

Some spiral showerheads allow for the addition of a supplemental gas tobe injected into the processing chamber while maintaining the separationbetween the supplemental gas and the gases flowing along the length ofthe spiral channels. The supplemental gas may be used, for example, forprocess enhancement or cleaning. In one or more embodiments, asupplemental gas flow path through an edge injector ring is added touniformly distribute a supplemental gas around the top edge of thesubstrate without mixing with the other process chemistries flowingthrough the spiral showerhead channels. Gas for the supplemental channelcan be split into two or more paths using gaslines before connecting tothe edge ring. The supplemental gas can flow into a channel (plenum) inthe edge ring which distributes the gas evenly before exiting outthrough small trenches spaced around the ring. The gas passes through agap between the edge ring inner diameter surface and the spiralshowerhead outer diameter surface.

With reference to FIGS. 18-21, one or more embodiments of the disclosureare directed substrate processing chambers 1800 including a gasdistribution apparatus 1805 with a gas distribution plate 1900 and edgering 2000. The substrate processing chamber includes a substrate support1810 having a top surface 1812 to support a substrate 1804. A processregion 1850 is bounded by the top surface 1812 of the substrate support1810, on the sides by a confinement ring 1820 and on the top by the gasdistribution plate 1900.

The gas distribution plate 1900 has an outer peripheral edge 1902, afront side 1906 and a back side 1904. At least one delivery channel 1903a, 1903 b is recessed in the back side 1904 of a gas distribution plate199. As shown in the embodiment of FIG. 9, the at least one channel 902a, 902 b has an inlet end 904 a, 904 b, an outlet end 906 a, 906 b and alength. The delivery channel including a plurality of apertures 1908 a,1908 b spaced along the length extending through the gas distributionplate 1900 to the front side 1906 of the gas distribution plate 1900.

As shown in FIGS. 18 and 19, the edge ring 2000 is positioned around theouter peripheral edge 1902 of the gas distribution plate 1900. The edgering 2000 has a round body with a top 2012, bottom 2014, inner diameter2015 with an inner diameter face 2016 and an outer diameter 2017 with anouter diameter face 2018. FIG. 20 shows a cross-section of an edge ring2000 shown in perspective.

Referring back to FIGS. 18 and 19, the edge ring 2000 is positioned sothat there is a gap 2030 between the outer peripheral edge 1902 of thegas distribution plate 1900 and the inner diameter face 2016 of the edgering 2000. The size of the gap 2030 can be in the range of about 0.02 mmto about 3 mm. The gap 2030 can be uniform around the inner diameterface 2016 or can be formed as a plurality of channels or trenches 2040.

In some embodiments, the outer peripheral edge 1902 of the gasdistribution plate 1900 contacts the inner diameter face 2016 of theedge ring 2000 except at the trenches 2040 forming a plurality of gaps2030. The partial embodiment shown in FIG. 21 illustrates an edge ring2000 with a single trench 2040. When the inner diameter face 2016 of theedge ring 2000 is positioned to contact the outer peripheral edge 1902of the gas distribution plate 1900, the gap 2030 will be formed in theregion defined by the trench 2040. In some embodiments, the trenches2040 have a width (distance along the inner diameter face 2016) anddepth (distance into the inner diameter face 2016) and extend from a topof the inner diameter face 2016 to the bottom of the inner diameter face2016. The width and depth of the trenches 2040 can be variedindependently. In some embodiments, the width and/or depth of thetrenches in the range of about 0.02 mm to about 3 mm.

A plenum 2050 is formed in the top 2012 of the round body 2010 of theedge ring 2000. The plenum 2050 has an outer peripheral face 2052 and aninner peripheral face 2054 defining a width of the plenum. The volume ofthe plenum 2050 can vary depending on, for example, the size of the edgering 2000. In some embodiments, the plenum 2050 has a volume in therange of about 100 mL to about 900 mL, or in the range of about 200 mLto about 800 mL, or in the range of about 300 mL to about 700 mL, or inthe range of about 400 mL to about 600 mL, or about 500 mL.

The volume of gas in the plenum 2050 and the combined volume of theopenings 2070 and trenches 2040 may be related to increase theuniformity of gas flowing out of the trenches 2040. When referring tothe volume of the trenches 2040, those skilled in the art willunderstand that this includes the volume of the openings 2070 that areintegral with the trenches 2040. In some embodiments, the combinedvolume in the trenches 2040 for all of the trenches 2040 around theperiphery of the edge ring is in the range of about 20 mL to about 240mL, or in the range of about 40 mL to about 180 mL, or in the range ofabout 60 mL to about 120 mL.

The ratio of the combined volume of the trenches 2040 to the volume ofthe plenum 2050 may affect the gas uniformity. In some embodiments, theratio of a combined volume of the trenches 2040 to a volume of theplenum 2050 is in the range of about 10% to about 30%. In one or moreembodiments, the volume of the trenches 2040 is about 20% of the volumeof the plenum 2050.

A plurality of openings 2070 in the inner diameter face 2016 of theplenum 205 form a plurality of channels connecting the plenum 2050 withthe gap 2030. In the embodiment shown in FIG. 21, the channel opening2070 is aligned with and continuous with the trench 2040. The pluralityof openings 2070 and/or trenches 2040 of some embodiments aresubstantially equally spaced about the inner diameter face 2016. As usedin this regard, the term “substantially equally spaced” means that thereis no more than a 10% relative difference in the average distancebetween each opening 2070 around the inner diameter face 2016. As shownin FIG. 20, there can be any suitable number of trenches 2040 andopenings 2070 around the inner diameter face 2016. In some embodiments,there is in the range of about 12 and about 120 openings 2070 in theinner diameter face 2016. In some embodiments, there is about 36openings 2070 in the inner diameter face 2016 and each of the openings2070 are aligned with and continuous with a trench 2040.

FIG. 22 shows a cross-sectional view shown at trench 2040. There is agap 2030 between the inner diameter face 2016 and the outer peripheraledge 1902. The gap 2030 between the inner diameter face 2016 of theouter distribution ring 2000 and the outer peripheral edge 1902 of thegas distribution plate 1900 is shaped to direct a gas to flow down theinner diameter face 2016 within the trench 2040. The gas flows from theplurality of trenches 2040 out the front side 1906 of the gasdistribution apparatus 1900. The direction or angle that the gas flowsout of the gap 2030 can be varied from angled inward toward the centralaxis of the outer distribution ring 2000 to angled outward from thecentral axis. In some embodiments, the gas flows out of the gap 2030 adirection substantially concentric with the central axis of the body2010 of the outer distribution ring 2000. A direction substantiallyconcentric with the central axis means that the gas is flowing out ofthe gap 2030 along a path parallel to the central axis.

At least one gas inlet 2060 is in fluid communication with the plenum2050 so that a gas can flow through inlet line 2062 and gas inlet 2060into the plenum 2050. In some embodiments, as shown in FIG. 19, the gasinlet 2060 connects to the plenum 2050 through the top 2012 of the body2010 of the outer distribution ring 2000. In some embodiments, as shownin FIG. 23, the gas inlet 2060 connects to the plenum 2050 through theouter diameter face 2018 of the body 2010. Some embodiments are directedto an outer distribution ring 2000 that might be retrofit into anexisting processing chamber. In this case, there may not be sufficientroom above the existing gas distribution assembly to allow foradditional gas inlets.

As shown in FIG. 24, some embodiments include a second plenum 2057. Thesecond plenum 2057 may allow for the further equalization of gaseswithin the plenum 2050 before flowing into the process region throughthe trench 2040. The second plenum 2057 can be located in any suitableposition and may be located between the gas inlet 2060 and the plenum2050. The second plenum 2057 is in fluid communication with the plenum2050 through a plurality of apertures 2058. There can be any number ofapertures 2058 extending around the body 2010. In some embodiments,there is in the range of about 36 apertures to about 720 apertures.

FIG. 25 shows another embodiment similar that that of FIG. 20. In theembodiment of FIG. 25, the edge ring 2000 is positioned so that there isa gap 2030 (see FIGS. 18 and 19) between the outer peripheral edge 1902of the gas distribution plate 1900 and the inner diameter face 2016 ofthe edge ring 2000. The size of the gap 2030 can be in the range ofabout 0.02 mm to about 3 mm. In the embodiment shown, the gap 2030 issubstantially uniform around the inner diameter face 2016 so that thetrenches 2040 of FIG. 20 are not included.

A plenum 2050 is formed in the top 2012 of the round body 2010 of theedge ring 2000. The plenum 2050 has an outer peripheral face 2052 and aninner peripheral face 2054 defining a width of the plenum. The volume ofthe plenum 2050 can vary depending on, for example, the size of the edgering 2000. In some embodiments, the plenum 2050 has a volume in therange of about 100 mL to about 900 mL, or in the range of about 200 mLto about 800 mL, or in the range of about 300 mL to about 700 mL, or inthe range of about 400 mL to about 600 mL, or about 500 mL.

The volume of gas in the plenum 2050 and the combined volume of theopenings 2070 may be related to increase the uniformity of gas flowingout of the openings 2070. In some embodiments, the combined volume inthe openings 2070 around the periphery of the edge ring is in the rangeof about 2 mL to about 240 mL, or in the range of about 20 mL to about180 mL, or in the range of about 60 mL to about 120 mL.

The ratio of the combined volume of the openings 2070 to the volume ofthe plenum 2050 may affect the gas uniformity. In some embodiments, theratio of a combined volume of the openings 2070 to a volume of theplenum 2050 is in the range of about 10% to about 30%. In one or moreembodiments, the volume of the openings 2070 is about 20% of the volumeof the plenum 2050.

The plurality of openings 2070 of some embodiments are substantiallyequally spaced about the inner diameter face 2016. As used in thisregard, the term “substantially equally spaced” means that there is nomore than a 10% relative difference in the average distance between eachopening 2070 around the inner diameter face 2016. As shown in FIG. 25,there can be any suitable number of openings 2070 around the innerdiameter face 2016. In some embodiments, there is in the range of about12 and about 120 openings 2070 in the inner diameter face 2016. In someembodiments, there is about 36 openings 2070 in the inner diameter face2016 and each of the openings 2070 are aligned with and continuous witha trench 2040.

Referring to FIGS. 18 and 19, some embodiments include a temperaturecontrol element 1830. The temperature control element 1830 can be aheater or cooler and can be used to maintain a set temperature for theprocess gases flowing through channels 1903 a, 1903 b. A gas inlet 1840can also be connected to the gas distribution plate 1900 either throughthe temperature control element 1830 or directly to the gas distributionplate 1900. The gas inlet 1840 is shown in the middle of the gasdistribution plate 1900 but those skilled in the art will understandthat this can be positioned in any suitable location and can be anysuitable size.

The confinement ring 1820 helps contain the process gases in the processregion 1850. The confinement ring 1820 shown in FIGS. 18 and 19 includesa plurality of openings 1822 to allow a flow of gas to pass from theprocess region 1850 to exhaust out of the processing chamber. The gasflowing through the gap 2030 flows into an outer edge region 1851 of theprocess region 1850. The gas flow in the outer edge region 1851 mixeswith gases from the center of the process region 1850. The mixed gasesflow through the openings 1822 to exhaust. In some embodiments, the useof the gas flowing through the outer distribution ring 2000 increasesthe uniformity of deposition around the edges of the substrate 1804.

Referring to FIGS. 18 and 26, some embodiments have multiple gas inlets2060. In the embodiments shown, there are two gas inlets 2060 connectedto the outer distribution ring 2000. The gas inlets 2060 can haveindependent gas supplies or can share a gas supply. In some embodiments,the gas inlets 2060 share a single gas supply that is split at ajunction 2064. In the embodiment shown, a first gas line segment 2063,which may be connected to a gas source, is in fluid communication with ajunction 2064 that splits the first gas line segment 2063 into twosecond gas line segments which become the inlet line 2062 which isconnected to the gas inlet 2060. There can be any suitable number of gasinlets 2060 around the outer distribution ring 2000. In someembodiments, there are in the range of about 1 to about 12 gas inlets,or in the range of about 2 to about 6 gas inlets. In some embodiments,there are two gas inlets, or four gas inlets. There can be any suitablenumber of gas sources connected to the inlets. For example, anembodiment with four gas inlets may have one, two, three or four gassources. A single gas source could be split into four gas line segments.To increase the uniformity of gas flowing into the outer distributionring 2000, the second gas line segments have substantially the same gasconductance. As used in this regard, the term “substantially the samegas conductance” means that the conductance through any second gas linesegment is within ±10% of the average conductance through all of thesecond gas line segments.

In some embodiments, a supplemental gas inlet 2092 is in fluidcommunication with a supplemental gas line 2090. The supplemental gasinlet 2092 allows the supplemental gas flowing through the supplementalgas line 2090 to pass through the gas distribution apparatus 1805 toflow the supplemental gas into the process region 1850. The supplementalgas can be any suitable gas including, but not limited to, reactivegases, inert gases and cleaning gases. The supplemental gas inlet 2092can route the gas flow through any portion of the gas distributionapparatus 1805 that does not interfere with the gas flows of the outerdistribution ring 2000 or the gas distribution plate 1900.

FIG. 27 shows a cross-sectional view of an embodiment of an outerdistribution ring 2000 that includes a supplemental gas inlet 2092 inthe outer diameter face 2018 of the outer distribution ring 2000. Thesupplement gas can be connected to the supplemental gas inlet 2092 toflow into the optional supplemental plenum 2096 and into the processregion 1850 through supplemental gas channel 2094. There can be anysuitable number of supplemental gas channels 2094 distributed around theperiphery of the outer distribution ring 2000. In use, for example, tworeactive gases can be flowed into the process region 1850 through thegas distribution plate 1900 while an inert gas is flowed into the outeredge region 1851 of the process region 1850. The inert gas in the outeredge region 1851 may help force the flow of reactive gases from theprocess region 1850 through openings 1822 to exhaust. After processing,the reactive gas flow through the gas distribution plate 1900 and theinert gas flow through the outer distribution ring 2000 can be stoppedand the flow of supplemental gas through the supplemental gas inlet 2092can be started. This may allow for the admission of an etchant orcleaning gas into the process region 1850 through a dedicated gas line.Those skilled in the art will understand that there can be any suitablenumber of supplemental gas lines connected to the process region 1850through the outer distribution ring 2000 or the gas distribution plate1900. Those skilled in the art will also recognize that there are otherprocessing sequences that can be employed without deviating from thescope of the disclosure.

The gas distribution apparatus described can be used to form one or morelayers during a plasma enhanced atomic layer deposition (PEALD) process.In some processes, the use of plasma provides sufficient energy topromote a species into the excited state where surface reactions becomefavorable and likely. Introducing the plasma into the process can becontinuous or pulsed. In some embodiments, sequential pulses ofprecursors (or reactive gases) and plasma are used to process a layer.In some embodiments, the reagents may be ionized either locally (i.e.,within the processing area) or remotely (i.e., outside the processingarea). Remote ionization can occur upstream of the deposition chambersuch that ions or other energetic or light emitting species are not indirect contact with the depositing film. In some PEALD processes, theplasma is generated external from the processing chamber, such as by aremote plasma generator system. The plasma may be generated via anysuitable plasma generation process or technique known to those skilledin the art. For example, plasma may be generated by one or more of amicrowave (MW) frequency generator or a radio frequency (RF) generator.The frequency of the plasma may be tuned depending on the specificreactive species being used. Suitable frequencies include, but are notlimited to, 2 MHz, 13.56 MHz, 40 MHz, 60 MHz and 100 MHz. Althoughplasmas may be used during the deposition processes disclosed herein, itshould be noted that plasmas may not be required.

According to one or more embodiments, the gas distribution apparatus canbe used to subject a substrate to processing prior to and/or afterforming the layer. This processing can be performed in the same chamberor in one or more separate processing chambers. In some embodiments, thesubstrate is moved from the first chamber to a separate, second chamberfor further processing. The substrate can be moved directly from thefirst chamber to the separate processing chamber, or it can be movedfrom the first chamber to one or more transfer chambers, and then movedto the desired separate processing chamber. Accordingly, the processingapparatus may comprise multiple chambers in communication with atransfer station. An apparatus of this sort may be referred to as a“cluster tool” or “clustered system”, and the like.

Generally, a cluster tool is a modular system comprising multiplechambers which perform various functions including substratecenter-finding and orientation, degassing, annealing, deposition and/oretching. According to one or more embodiments, a cluster tool includesat least a first chamber and a central transfer chamber. The centraltransfer chamber may house a robot that can shuttle substrates betweenand among processing chambers and load lock chambers. The transferchamber is typically maintained at a vacuum condition and provides anintermediate stage for shuttling substrates from one chamber to anotherand/or to a load lock chamber positioned at a front end of the clustertool. Two well-known cluster tools which may be adapted for the presentdisclosure are the Centura® and the Endura® both available from AppliedMaterials, Inc., of Santa Clara, Calif. However, the exact arrangementand combination of chambers may be altered for purposes of performingspecific steps of a process as described herein. Other processingchambers which may be used include, but are not limited to, cyclicallayer deposition (CLD), atomic layer deposition (ALD), chemical vapordeposition (CVD), physical vapor deposition (PVD), etch, pre-clean,chemical clean, thermal treatment such as RTP, plasma nitridation,degas, orientation, hydroxylation and other substrate processes. Bycarrying out processes in a chamber on a cluster tool, surfacecontamination of the substrate with atmospheric impurities can beavoided without oxidation prior to depositing a subsequent film.

According to one or more embodiments, the substrate is continuouslyunder vacuum or “load lock” conditions, and is not exposed to ambientair when being moved from one chamber to the next. The transfer chambersare thus under vacuum and are “pumped down” under vacuum pressure. Inertgases may be present in the processing chambers or the transferchambers. In some embodiments, an inert gas is used as a purge gas toremove some or all of the reactants after forming the silicon layer onthe surface of the substrate. According to one or more embodiments, apurge gas is injected at the exit of the deposition chamber to preventreactants from moving from the deposition chamber to the transferchamber and/or additional processing chamber. Thus, the flow of inertgas forms a curtain at the exit of the chamber.

A substrate can be processed in single substrate deposition chambersusing, for example, the gas distribution apparatus described. In suchchambers, a single substrate is loaded, processed and unloaded beforeanother substrate is processed. A substrate can also be processed in acontinuous manner, like a conveyer system, in which multiple substrateare individually loaded into a first part of the chamber, move throughthe chamber and are unloaded from a second part of the chamber. Theshape of the chamber and associated conveyer system can form a straightpath or curved path. Additionally, the processing chamber may be acarousel in which multiple substrates are moved about a central axis andare exposed to deposition, etch, annealing, cleaning, etc. processesthroughout the carousel path.

During processing, the substrate can be heated or cooled. Such heatingor cooling can be accomplished by any suitable means including, but notlimited to, changing the temperature of the substrate support andflowing heated or cooled gases to the substrate surface. In someembodiments, the substrate support includes a heater/cooler which can becontrolled to change the substrate temperature conductively. In one ormore embodiments, the gases (either reactive gases or inert gases) beingemployed are heated or cooled to locally change the substratetemperature. In some embodiments, a heater/cooler is positioned withinthe chamber adjacent the substrate surface to convectively change thesubstrate temperature.

The substrate can also be stationary or rotated during processing. Arotating substrate can be rotated continuously or in discrete steps. Forexample, a substrate may be rotated throughout the entire process, orthe substrate can be rotated by a small amount between exposure todifferent reactive or purge gases. Rotating the substrate duringprocessing (either continuously or in steps) may help produce a moreuniform deposition or etch by minimizing the effect of, for example,local variability in gas flow geometries.

Although the disclosure herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent disclosure. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present disclosure without departing from the spiritand scope of the disclosure. Thus, it is intended that the presentdisclosure include modifications and variations that are within thescope of the appended claims and their equivalents.

What is claimed is:
 1. An outer distribution ring comprising a roundbody having a top, bottom, inner diameter with an inner diameter faceand an outer diameter with an outer diameter face; a plenum formed inthe top of the round body, the plenum having an outer peripheral faceand an inner peripheral face defining a width and having a volume in arange of about 100 mL to about 900 mL; and a plurality of openings inthe inner peripheral face of the plenum forming a plurality of trenchesconnecting the plenum with the inner diameter face, the plurality oftrenches substantially equally spaced about the inner peripheral face,the plurality of trenches extending from a top of the inner diameterface to a bottom of the inner diameter face, and the trenches having acombined volume in a range of about 20 mL to about 240 mL, wherein aratio of the combined volume of the trenches to the volume of the plenumis in the range of about 10% to about 30%.
 2. The outer distributionring of claim 1, wherein the plenum has a volume in the range of about400 mL to about 600 mL.
 3. The outer distribution ring of claim 2,wherein the trenches have a combined volume in the range of about 40 mLto about 180 mL.
 4. The outer distribution ring of claim 1, furthercomprising a second plenum in fluid communication with the plenumthrough a plurality of apertures.
 5. The outer distribution ring ofclaim 1, wherein the inner diameter face is shaped so that a gas flowingdown the inner diameter face from the plurality of trenches flowssubstantially concentric with an axis of the body.
 6. The outerdistribution ring of claim 1, further comprising a gas inlet in fluidcommunication with the plenum.
 7. The outer distribution ring of claim6, wherein the gas inlet connects to the plenum through the top of thebody.
 8. The outer distribution ring of claim 6, wherein the gas inletconnects to the plenum through the outer diameter face of the body.